Safety and efficacy of conversion therapy for esophageal squamous cell carcinoma.

Abstract

362 Background: The increased efficacy of multimodality treatment allows for the consideration of conversion therapy with curative intent for initially unresectable esophageal squamous cell carcinoma (ESCC) after initial treatment. Conversion therapy has been commonly defined as treatment aiming at a curable intention after tumors initially deemed technically or oncologically unresectable or only marginally resectable respond to chemotherapy. In our institute, conversion therapy is considered for patients with para-aortic lymph node-positive advanced ESCC who have no other distant metastasis, if the para-aortic lymph node metastases have disappeared after systemic chemotherapy. Methods: There were 33 patients of unresectable esophageal cancer with positive para-aortic lymph node metastases from 2011 to 2021. Nine of these patients showed disappearance of para-aortic lymph node metastases and underwent conversion therapy, seven patients underwent esophagectomy and two patients underwent chemoradiation therapy (CRT). Characteristics, short-term and long-term results of these nine cases are studied. Results: All of the nine patients who had para-aortic lymph node metastases were treated with induction DCF (Docetaxel + Cisplatin + 5-FU) therapy as initial treatment. After disappearance of para-aortic lymph node metastasis, minimally invasive or open esophagectomy was performed in seven patients and CRT was performed in two patients. In operation group, four patients (57%) had Clavien-Dindo grade 2 or 3 complications, but no perioperative death was observed. In CRT group, there was no toxicity over CTCAE grade 3. Four of nine patients (44%) had recurrence, within mediastinum lymph node, abdominal lymph node or adrenal gland. 3-year DFS was 56% and 3-year OS was 67%. Conclusions: Conversion therapy is safe and feasible in cases that responded to systemic chemotherapy. Some cases showed good prognosis. Long-term survival is expected with conversion therapy. In our study, there was few cases that could led to conversion therapy. It is expected that more aggressive initial chemotherapy will be used in the future for patients with positive para-aortic lymph node metastases with a view to conversion therapy.